Product Introduction 
The paper dirt tester uses the visual comparison method. A standard-sized specimen of paper or paperboard is placed flat on the rotating worktable. Under illumination from a 20W standard fluorescent lamp, the observer examines the specimen surface from a specified angle to identify fiber bundles, dirt specks, and impurities that differ significantly in color from the background. These are compared with standard dirt charts for size and quantity assessment, and the dirt count is calculated according to the method specified in GB/T 1541-1989. The 360° rotating worktable facilitates inspection of all areas of the specimen. The instrument is simple in structure, easy to operate, requires no chemical reagents, and is a classic standard device for evaluating the visual cleanliness of paper.

Key Features
Strict National Standard Compliance Designed and manufactured in full accordance with GB/T 1541-1989, with standardized test methods and evaluation criteria for highly comparable data.
Standard Fluorescent Light Source Uses a 20W fluorescent lamp with a 60° irradiation angle, simulating natural light conditions to ensure illumination consistency across test batches.
360° Rotating Worktable The worktable rotates 360° with an effective area of 0.0625 m², facilitating inspection of dirt distribution on the specimen surface from any angle.
Standard Dirt Comparison Charts Equipped with standard dirt charts ranging from 0.05 to 5.0 mm for direct visual comparison to determine dirt size and grade, enabling intuitive operation.
Robust Structure, Easy Operation The unit consists of a base, rotating worktable, and light source; the structure is simple, requiring no specialized training, suitable for high-frequency routine inspection.
Suitable for Various Paper Types Applicable for surface dirt determination of all types of paper, paperboard, packaging paper, and specialty papers, covering the broad needs of the paper industry.
Easy Light Source Replacement Uses a universal 20W fluorescent tube for convenient replacement and low maintenance costs.
Durable and Reliable Design Overall dimensions of 750×350×500 mm, weight approximately 12.5 kg; robustly constructed for long-term use in both laboratory and production floor environments.

Main Technical Specifications 

FAQ 
1. What types of paper are suitable for the Paper Dirt Tester?
It is suitable for dirt determination of all types of paper and paperboard, including cultural papers, packaging papers, tissue papers, and specialty papers. As long as the specimen can be placed flat on the worktable, testing can be performed according to the standard method.

2. How is the dirt size and grade determined during testing?
Place the specimen on the worktable and examine its surface under the fluorescent lamp. Identify any dirt specks or impurities that differ distinctly in color from the background. Compare them with the standard dirt charts to determine the area size of each dirt, then count and calculate the dirt count according to the method specified in GB/T 1541-1989.

3. Why is the worktable designed to rotate?
The 360° rotating worktable allows the operator to observe the specimen surface from different angles, avoiding missed detections caused by lighting angle or viewing direction, ensuring comprehensive inspection of all areas of the specimen.

4. How should the standard dirt charts be stored and used?
The standard dirt charts should be kept clean and flat, avoiding folding and contamination. During use, place them beside the specimen for comparison. Periodically check the charts for fading or damage, and replace them with new standard charts as necessary.

5. Does the fluorescent lamp need to be replaced periodically?
It is recommended to periodically check the brightness and illumination uniformity of the fluorescent lamp. If the ends of the tube become blackened, the brightness noticeably decreases, or the lamp flickers, it should be replaced promptly to ensure the light source meets the standard-specified illumination conditions.

6. Does the testing environment affect the results?
Testing should be conducted indoors with soft lighting and no interference from strong external light sources. Avoid direct sunlight on the worktable surface, and ensure the fluorescent lamp is the primary light source for observing the specimen to maintain consistency in judgment.

After-Sales Service
Established in 2007 and with nearly two decades of experience, Shandong Annimet Instrument Co., Ltd. is a professional manufacturer integrating R&D, production, and sales of laboratory testing and sample preparation equipment. Quality is our foundation. We are your bridge from concept to reality. We deliver more than just instruments — we deliver confidence. This Paper Dirt Tester comes with a 12-month warranty and lifetime technical support. Our professional team offers 24/7 service response, free installation guidance, operation training, and dirt testing method consultation. For any inquiries, please contact our customer service team; we are dedicated to providing comprehensive pre-sales, in-sales, and after-sales support. Hotline: 400-9933-057, Email: anmt_test@126.com.